Image display system, apparatus for supporting material provision, and apparatus for acquiring material

ABSTRACT

An image display system including a display control device and terminals is provided. Each of the terminals includes a processor configured to: extract, from a photograph photographed for a specific period, an image representing a code for identifying a material stored in a server; and obtain the code by decoding the image, and a receiver configured to obtain a material from the server based on the code obtained. The display control device includes a controller configured to control the display to display the image. In a first terminal of the terminals, the specific period is a first period. In a second terminal of the terminals, the specific period is a second period. The controller controls the display to display a particular image as the image for the first period. The particular image represents, as the code, a code for identifying a particular material.

The entire disclosure of Japanese Patent application No. 2017-142514,filed on Jul. 24, 2017, is incorporated herein by reference in itsentirety.

BACKGROUND 1. Technological Field

The present invention relates to a technology for displaying an image ofa material, etc. in a presentation, and so on.

2. Description of the Related Art

Presentation applications, e.g., PowerPoint by Microsoft Corporation andKeynote by Apple Inc., have attained widespread use. Such applicationsare generally called “presentation software”. Such presentation softwareenables a user to create a material used in a meeting or presentation.Such presentation software also enables the created material to bedisplayed via a projector or display unit.

The presentation software is suitable especially for creating anddisplaying a material having a summarized content to be discussed in ameeting or presentation.

The following technologies have been proposed as technologies related todisplay devices. According to one of the technologies, a video signaloutput device generates a QR code (registered trademark) from codedoriginal data and acquires a video signal and inserts the generated QRcode into the acquired video signal in such a manner that the QR code ishardly recognized with naked eyes when displayed on the display device,and outputs the video signal with the code generated by inserting the QRcode to display it on the display device. A mobile phone provided with acamera causes the camera to photograph the QR code displayed on thedisplay device in such a manner that it is hardly recognized with nakedeyes, and decodes the QR code photographed by the camera and stores dataresulting from decoding it, in a storage medium (English abstract ofJapanese Unexamined Patent Application Publication No. 2006-128900).

According to the other technology, a projection device includes: a videoterminal that acquires first projection image data; a light source thatflickers in a first period; a projection control unit that causes aprojection unit to project a first projection image based on the firstprojection image data on the basis of the flicker of the light source,and causes the projection unit to project encoded information obtainedby encoding radio connection information for establishing radioconnection for a period of time based on the first period for everysecond period longer than the first period; and an establishing unitthat establishes radio connection with a terminal device on the basis ofa radio connection request based on the radio connection informationfrom the terminal device obtained by photographing to decode theprojected encoded information (English abstract of Japanese UnexaminedPatent Application Publication No. 2015-158596).

In the meantime, a material with detailed content is not suitable forbeing displayed in a presentation because such a material has too manycharacters. A supplementary material is not suitable for being displayedin a presentation because a speaker does not have enough time to giveexplanation for the material. Accordingly, such materials are oftenprinted out and distributed to attendees of the presentation.

For the distribution to the attendees, such materials need to be printedout and prepared in advance of the presentation.

In some cases, materials with content different depending on theattributes of attendees are prepared and distributed selectively to theattendees. For example, a material including classified information isprepared and given to supervisory employees, and a material having noclassified information is prepared and given to the other employees.Alternatively, a certain material is given only to the supervisoryemployees in some cases.

Where different materials need to be prepared depending on theattributes of attendees in this way, a large burden is placed on anorganizer of a meeting or seminar.

SUMMARY

The present invention has been achieved in light of such a problem, andtherefore, an object of an embodiment of the present invention is toenable distribution of materials to each of attendees more easily thanis conventionally possible.

To achieve at least one of the abovementioned objects, according to anaspect of the present invention, an image display system reflecting oneaspect of the present invention is an image display system including adisplay control device configured to control a display unit to displayan image, and a plurality of terminals. Each of the terminals includes ahardware processor configured to: extract, from an image photographedfor a specific period of time, a code image representing a code foridentifying a material stored in a server; and obtain the code bydecoding the code image, and a receiver configured to obtain a materialfrom the server based on the code obtained by the hardware processor.The display control device includes a controller configured to controlthe display unit to display the code image. In a first terminal of theterminals, the specific period of time is a first period of time, and ina second terminal of the terminals, the specific period of time is asecond period of time that does not overlap the first period of time.The controller controls the display unit to display a particular codeimage as the code image for the first period of time, the particularcode image representing, as the code, a code for identifying aparticular material.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features provided by one or more embodiments of theinvention will become more fully understood from the detaileddescription given hereinbelow and the appended drawings which are givenby way of illustration only, and thus are not intended as a definitionof the limits of the present invention.

FIG. 1 is a diagram showing an example of the overall configuration of amaterial display system.

FIG. 2 is a diagram showing an example of the hardware configuration ofa material server.

FIG. 3 is a diagram showing an example of the hardware configuration ofa main terminal.

FIG. 4 is a diagram showing an example of the hardware configuration ofa subsidiary terminal.

FIG. 5 is a diagram showing an example of the functional configurationof each of a material server and a subsidiary terminal.

FIG. 6 is a diagram showing an example of the functional configurationof a main terminal.

FIG. 7 is a diagram showing an example of a main material.

FIG. 8 is a diagram showing an example of listener data.

FIG. 9 is a diagram showing an example of subsidiary material attributesdata.

FIG. 10 is a diagram showing an example of reference data.

FIG. 11 is a flowchart depicting an example of the flow of patterndetermination processing.

FIGS. 12A-12D are diagrams showing examples of a recognition periodpattern.

FIGS. 13A and 13B are diagrams showing examples of a transition of animage displayed by a projector.

FIG. 14 is a flowchart depicting an example of the flow oftwo-dimensional barcode display processing.

FIG. 15 is a flowchart depicting an example of the flow oftwo-dimensional barcode acquisition processing.

FIG. 16 is a flowchart depicting an example of the flow of the entireprocessing by a main terminal.

FIG. 17 is a flowchart depicting an example of the flow of the entireprocessing by a subsidiary terminal.

FIGS. 18A-18C are timing charts depicting examples of a time at which aspecific listener and a non-specific listener each photographs with asubsidiary terminal.

FIG. 19 is a timing chart depicting a modified example of a time atwhich a specific listener and a non-specific listener each photographswith a subsidiary terminal.

FIGS. 20A and 20B are diagrams showing examples of restoration of afirst two-dimensional barcode.

FIGS. 21A-21D are timing charts depicting examples of a time ofrecognition and display when three files are distributed selectively.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, one or more embodiments of the present invention will bedescribed with reference to the drawings. However, the scope of theinvention is not limited to the disclosed embodiments.

FIG. 1 is a diagram showing an example of the overall configuration of amaterial display system 100. FIG. 2 is a diagram showing an example ofthe hardware configuration of a material server 1. FIG. 3 is a diagramshowing an example of the hardware configuration of a main terminal 2.FIG. 4 is a diagram showing an example of the hardware configuration ofa subsidiary terminal 3.

Referring to FIG. 1, the material display system 100 is configured ofthe material server 1, the main terminal 2, a plurality of thesubsidiary terminals 3, a projector 41, an image forming apparatus 42, acommunication line 5, and so on.

The material display system 100 is installed in an organization such asa corporation, government office, or school. The material display system100 is to display a material (document) in a meeting or presentationmade in the organization to allow attendees thereof to look at thematerial displayed. Description is provided below by taking an exampleof the use of the material display system 100 for a presentation thatsupervisory employees and non-supervisory employees attend.

The material server 1, the main terminal 2, the projector 41, thesubsidiary terminals 3, and the image forming apparatus 42 areconfigured to perform communication with one another via thecommunication line 5. Examples of the communication line 5 include apublic line, the Internet, and a Local Area Network (LAN). The LANincludes a router, a hub, a twisted pair cable, and a wireless basestation, which enables both wired communication and wirelesscommunication.

The material server 1 serves to manage files for materials display andsends data to the main terminal 2 or the projector 41.

Referring to FIG. 2, the material server 1 is configured of a CentralProcessing Unit (CPU) 10 a, a Random Access Memory (RAM) 10 b, a ReadOnly Memory (ROM) 10 c, an auxiliary storage 10 d, a Network InterfaceCard (MC) 10 e, and so on.

The MC 10 e performs communication with the main terminal 2 and thesubsidiary terminals 3 in accordance with a protocol such asTransmission Control Protocol/Internet Protocol (TCP/IP).

The ROM 10 c or the auxiliary storage 10 d stores, therein, a fileserver program 10P (see FIG. 5) as one of computer programs. The fileserver program 10P is to manage files and to provide a file in responseto a request made by the main terminal 2 or the subsidiary terminals 3.The auxiliary storage 10 d also stores, therein, files on amaterial-by-material basis.

The file server program 10P is loaded into the RAM 10 b and is executedby the CPU 10 a. Examples of the auxiliary storage 10 d are a hard diskdrive and a Solid State Drive (SSD).

The material server 1 is a so-called file server, for example. Thematerial server 1 may be a Network Attached Storage (NAS) or a cloudserver. The cloud server is sometimes called an “online storage”.

The main terminal 2 is connected to the projector 41. The main terminal2 causes the projector 41 to display a material primarily used in apresentation (hereinafter, referred to as a “main material 6A”) on aprojector screen or a wall surface. The main terminal 2 is operated by auser who makes a presentation or an assistant. Hereinafter, such a useris referred to as a “speaker 28”. The following description takes anexample where an image of a material or the like is displayed(projected) on the projector screen and the speaker 28 operates the mainterminal 2.

The main terminal 2 is, for example, a laptop personal computer, atablet computer, or a smartphone. The following description takes anexample where the main terminal 2 is a laptop personal computer.

Referring to FIG. 3, the main terminal 2 is configured of a CPU 20 a, aRAM 20 b, a ROM 20 c, an auxiliary storage 20 d, a display 20 e 1, acontroller 20 e 2, a keyboard 20 f, a pointing device 20 g, a wirelesscommunication device 20 h, an image output interface 20 i, a clock 20 j,and so on.

The keyboard 20 f and the pointing device 20 g are used for the speaker28 to enter a command or information.

The display 20 e 1 serves to display the main material 6A in accordancewith a command or the like entered by the speaker 28. To be specific,the controller 20 e 2 generates, based on a command from the CPU 20 a, asignal for an image displayed in the display 20 e 1, e.g., the mainmaterial 6A, and sends the signal to the display 20 e 1. The display 20e 1 displays an image based on the signal. In this way, the display 20 e1 is controlled by the controller 20 e 2.

The wireless communication device 20 h connects to a wireless basestation of the communication line 5 based on the standard for aso-called wireless LAN, specifically, the standard for Institute ofElectrical and Electronics Engineers (IEEE) 802.11 to performcommunication with the material server 1, the subsidiary terminals 3,the projector 41, the image forming apparatus 42, and so on inaccordance with a protocol such as TCP/IP.

The image output interface 20 i is a circuit for outputting an imagesignal. The image output interface 20 i is, for example, theHigh-Definition Multimedia Interface (HDMI) (registered trademark) or acircuit complying with the analog RGB standard.

The clock 20 j serves to measure a current time. The clock 20 j connectsto a Network Time Protocol (NTP) server at regular intervals (every day,for example) and corrects the time.

The ROM 20 c or the auxiliary storage 20 d stores, therein, apresentation program 20P (see FIG. 6) as one of the computer programs.The presentation program 20P is a so-called presentation tool such asPowerPoint developed by Microsoft Corporation or Keynote developed byApple Inc.

The presentation program 20P is loaded into the RAM 20 b and executed bythe CPU 20 a. Examples of the auxiliary storage 20 d are a hard diskdrive and an SSD.

The subsidiary terminal 3 serves to display a subsidiary material 6B.The subsidiary material 6B is a supplementary material to be referred toby a user who watches and listens to the presentation. Such a user ishereinafter referred to as a “listener 38”.

The listener 38 operates the subsidiary terminal 3. Examples of thesubsidiary terminal 3 include portable devices such as a tablet computeror a smartphone. Hereinafter the case is descried in which thesubsidiary terminal 3 is a tablet computer.

Referring to FIG. 4, the subsidiary terminal 3 is configured of a CPU 30a, a RAM 30 b, a ROM 30 c, a flash memory 30 d, a touch-sensitive paneldisplay 30 e 1, a controller 30 e 2, an operation button group 30 f, awireless communication device 30 g, a digital camera 30 h, a clock 30 i,and so on.

As with the display 20 e 1, the touch-sensitive panel display 30 e 1displays a part or the whole of a document. To be specific, thecontroller 30 e 2 generates, based on a command from the CPU 30 a, asignal for an image displayed in the touch-sensitive panel display 30 e1, e.g., a part of the document, and sends the signal to thetouch-sensitive panel display 30 e 1. The touch-sensitive panel display30 e 1 displays an image based on the signal. In this way, thetouch-sensitive panel display 30 e 1 is controlled by the controller 30e 2. The touch-sensitive panel display 30 e 1 detects a touched locationand informs the CPU 30 a of the touched location.

The operation button group 30 f includes a button for returning to aso-called start screen, a button for controlling sound volume, and abutton for switching between ON and OFF of the power supply.

The wireless communication device 30 g performs communication via a basestation with the material server 1, the main terminal 2, the imageforming apparatus 42, and so on in accordance with a protocol such asTCP/IP based on the standard for wireless LAN.

The digital camera 30 h serves to take an image to generate image datathereof. In this embodiment, the digital camera 30 h is particularlyused, as described later, to photograph a two-dimensional barcode at atime when the subsidiary material 6B is downloaded.

The clock 30 i serves to measure a current time. As with the clock 20 jof the main terminal 2, the clock 30 i connects to the NTP server atregular intervals to correct the time.

The clock 20 j and the clock 30 i correct the time at regular intervalsas described above. This enables a synchronization to be achievedcorrectly between a time at which to display a two-dimensional barcodeby the main terminal 2 and the projector 41 and a time at which torecognize the two-dimensional barcode by the subsidiary terminals 3.

The ROM 30 c or the flash memory 30 d stores, therein, a material viewerprogram 30P (see FIG. 5) as one of the computer programs. The materialviewer program 30P is loaded into the RAM 30 b and executed by the CPU30 a.

The subsidiary terminal 3 is allocated to each listener 38. Thelisteners 38 are hereinafter referred to as a “listener 38A”, a“listener 38B”, a “listener 38C”, . . . and so on respectively todistinguish one from another. Likewise, the subsidiary terminals 3allocated to the listeners 38A, 38B, 38C, . . . , and so on arehereinafter referred to as a “subsidiary terminal 3A”, a “subsidiaryterminal 3B”, a “subsidiary terminal 3C”, and so on respectively todistinguish one from another.

The projector 41 serves to project an image onto the projector screenbased on image data sent by the main terminal 2. The projector 41 isprovided with at least one of an image input interface circuit, an NIC,and a wireless communication device as a means for receiving the imagedata from the main terminal 2. The image input interface circuit is, forexample, a circuit complying with the HDMI or the analogue RGB standard.The projector 41 is a commercially available projector.

The description goes on to an example in which the main terminal 2 sendsimage data to the projector 41 through the HDMI.

The image forming apparatus 42 is an apparatus into which functions suchas copying, PC printing, faxing, scanning, and a box function areintegrated. The image forming apparatus 42 is generally called a“Multi-Functional Peripheral (MFP)” or a “multifunction device”.

The PC printing function is to print an image onto paper based on theimage data received from the main terminal 2 or the subsidiary terminal3.

According to the box function, each user is given a storage area calleda “box” or a “personal box”. The box function enables each user to saveimage data and so on to his/her storage area and to manage the imagedata and so on therein. The box corresponds to a “folder” or a“directory” of a personal computer. The main material 6A and thesubsidiary material 6B may be managed in a box of the image formingapparatus 42 instead of the material server 1.

The description goes on to preparation of each of the main material 6Aand the subsidiary material 6B, and to processing performed by theindividual devices. The description is provided with reference to FIGS.5 to 15.

[Preparation of the Main Material 6A and the Subsidiary Material 6B]

FIG. 5 is a diagram showing an example of the functional configurationof each of the material server 1 and the subsidiary terminal 3. FIG. 6is a diagram showing an example of the functional configuration of themain terminal 2. FIG. 7 is a diagram showing an example of the mainmaterial 6A. FIG. 8 is a diagram showing an example of listener data 7C.FIG. 9 is a diagram showing an example of subsidiary material attributesdata 7D. FIG. 10 is a diagram showing an example of reference data 7A2.

The file server program 10P implements, in the material server 1, thefunctions of a subsidiary material storage portion 101, a subsidiarymaterial delivery portion 102, and so on, all of which are shown in FIG.5.

The presentation program 20P implements, in the main terminal 2, thefunctions of a main material storage portion 201, a listener datastorage portion 202, a subsidiary material attributes storage portion203, a main material display portion 204, a timing determination portion205, a timing notifying portion 206, a two-dimensional barcode displayportion 207, a photographing stop command portion 208, and so on, all ofwhich are shown in FIG. 6.

The material viewer program 30P implements, in the subsidiary terminal3, the functions of a photographing start portion 301, an imagecapturing portion 302, a two-dimensional barcode extraction portion 303,a text recognition portion 304, a subsidiary material obtaining portion305, a subsidiary material display portion 306, and so on, all of whichare shown in FIG. 5.

The main material storage portion 201 of the main terminal 2 stores,therein, a file 7A used for displaying the main material 6A. The speaker28 uses the presentation program 20P to prepare the file 7A by creatingthe main material 6A before starting the presentation. The file 7A thusprepared is stored into the main material storage portion 201.

Referring to FIG. 7, the main material 6A has a plurality of pages 6AP.The page is sometimes called a “slide” or “screen”, particularly, in apresentation application. The pages 6AP are hereinafter describedseparately as a “page 6AP1”, “page 6AP2”, “page 6AP3”, . . . and so onin order from Page 1. The pages 6AP are given page numbers of “1”, “2”,“3”, and so on in order from Page 1.

The file 7A includes display data 7A1 and reference data 7A2. Thedisplay data 7A1 is used to display each of the pages 6AP. The referencedata 7A2 is used when the listeners 38 refer to the subsidiary material6B in the presentation. Only one set of the reference data 7A2 isincluded in the file 7A in some cases, and a plurality of sets of thereference data 7A2 are included therein in other cases. The referencedata 7A2 is detailed later.

The subsidiary material storage portion 101 of the material server 1stores, therein, a file 7B used for displaying the subsidiary material6B. The speaker 28 uses word-processing software, spreadsheet software,rendering software, or the like to prepare the file 7B by creating thesubsidiary material 6B before starting the presentation. The file 7Bthus prepared is stored into the subsidiary material storage portion101. Alternatively, the speaker 28 may prepare the file 7B by downloadfrom a server over the Internet. The subsidiary material 6B may be adocument or a moving image.

When there are a plurality of subsidiary materials 6B, the speaker 28prepares the files 7B of the subsidiary materials 6B to store the files7B into the subsidiary material storage portion 101.

In some cases, the speaker 28 intends to show all the contents of acertain subsidiary material 6B to a listener 38 who takes a specificposition (managerial position, for example); however intends to showonly a part of the contents of the subsidiary material 6B to the otherlisteners 38. The subsidiary material 6B in such a case is hereinafterreferred to as a “first limited material”. The listener 38 who takes aspecific position is hereinafter referred to as a “specific listener”,and the other listeners 38 are referred to as “non-specific listeners”.

Alternatively, in some cases, the speaker 28 intends to show all thecontents of a certain subsidiary material 6B to the specific listener;however intends to show none of the contents of the subsidiary material6B to the non-specific listeners. In short, the speaker 28 intends toshow the certain subsidiary material 6B only to the specific listener insome cases. The subsidiary material 6B in such a case is hereinafterreferred to as a “second limited material”. Alternatively, a subsidiarymaterial 6B that may be shown to both the specific listener and thenon-specific listeners with no limitation is hereinafter referred to asa “no-limit material”.

The description goes on to the case where the specific position is amanagerial position, in other words, where a person who holds amanagerial position is the specific listener and the other persons arethe non-specific listeners.

As for the first limited material, the speaker 28 prepares, as the file7B, a file for specific listener and a file for non-specific listener.As for the no-limit material, the speaker 28 prepares only one file 7Bas the file 7B. As for the second limited material, the speaker 28prepares only one file 7B as the file 7B.

The case is hereinafter described in which four subsidiary materials 6B1to 6B4 are used as the subsidiary material 6B. Suppose that thesubsidiary materials 6B1 and 6B4 correspond to the first limitedmaterial, the subsidiary material 6B3 corresponds to the second limitedmaterial, and the subsidiary material 6B2 corresponds to the no-limitmaterial.

For the subsidiary material 6B1, the speaker 28 prepares, as the file7B, a file for specific listener and a file for non-specific listener.Hereinafter, the former file is called a “file 7B11” and the latter fileis called a “file 7B12”. Likewise, for the subsidiary material 6B4, thespeaker 28 prepares, as the file 7B, a file 7B41 for specific listenerand a file 7B42 for non-specific listener.

The speaker 28 prepares a file 7B2 as the file 7B for the subsidiarymaterial 6B2. The speaker 28 also prepares a file 7B3 as the file 7B forthe subsidiary material 6B3.

As shown in FIG. 8, the listener data storage portion 202 of the mainterminal 2 stores, therein, the listener data 7C for each of thelisteners 38. The listener data 7C indicates the following information.

The “user code” is an identifier of the listener 38 given thecorresponding listener data 7C. The “user name” is the name of thatlistener 38. The “device name” is the name of the subsidiary terminal 3allocated to that listener 38. The “IP address” is an IP address givento the subsidiary terminal 3.

The “access right” is a right, given to the corresponding listener 38,to view the subsidiary material 6B. As described above, the specificlistener is allowed to view all the contents of the subsidiary material6B with no limitation while the non-specific listeners are allowed toview only a part of the subsidiary material 6B. Where the listener 38corresponds to the specific listener, he/she is given an access right toview all the contents of the subsidiary material 6B. In such a case, asshown in FIG. 8, the “access right” indicates “full” which means theright to view all the contents of the subsidiary material 6B. Where thelistener 38 corresponds to the non-specific listener, he/she is given anaccess right to view a part of the subsidiary material 6B. In such acase, the “access right” indicates “some” which means the right to viewa part of the subsidiary material 6B.

The listener data 7C is prepared in advance by an administrator of thematerial display system 100 and is stored into the listener data storageportion 202.

Referring to FIG. 9, the subsidiary material attributes storage portion203 stores, therein, the subsidiary material attributes data 7D for eachof the subsidiary materials 6B. The subsidiary material attributes data7D indicates the following information.

The “material code” is an identifier of the subsidiary material 6Bcorresponding to the subject subsidiary material attributes data 7D.

The “delivery target” indicates attributes of the listeners 38 to whomthe subject subsidiary material 6B is to be delivered. As describedearlier, for each of the first limited material, the second limitedmaterial, and the no-limit material, how the content thereof is to beshown to each of the specific listener and the non-specific listeners isdetermined in advance. Where the subsidiary material 6B corresponds tothe first limited material, the delivery target indicates“attributes-specific”. Where the subsidiary material 6B corresponds tothe second limited material, the delivery target indicates “specificlistener”. Where the subsidiary material 6B corresponds to the no-limitmaterial, the delivery target indicates “all listeners”.

The “identification code” is to identify a file 7B for the subsidiarymaterial 6B. The “file name” is the name of the subject file 7B. Thefile name is used to differentiate the subject file 7B from other filesin the subsidiary material storage portion 101.

As mentioned above, however, two subsidiary materials 6B are preparedfor the first limited material. In view of this, where the subsidiarymaterial 6B corresponds to the first limited material, a code and a filename of the file 7B for the specific listener are indicated as theidentification code and the file name, respectively, and a code and afile name of the file 7B for the non-specific listener are indicated asa “second identification code” and a “second file name”, respectively.

In the meantime, when a specific page 6AP is displayed during apresentation, the speaker 28 sometimes wishes the listeners 38 to referto a specific subsidiary material 6B. In such a case, in preparing themain material 6A before the presentation, the speaker 28 performsoperation to correlate the specific page 6AP with the specificsubsidiary material 6B. In this embodiment, the speaker 28 enters a pagenumber of the page 6AP and a material code of the subsidiary material6B.

Where there are a plurality of combinations of a specific page 6AP and aspecific subsidiary material 6B to be referred to, the speaker 28 entersa page number of the specific page 6AP and a material code of thespecific subsidiary material 6B for each of the combinations.

The data indicating the page number and material code thus entered isstored as the reference data 7A2 into the main material storage portion201 as shown in FIG. 10.

[Processing During Presentation]

FIG. 11 is a flowchart depicting an example of the flow of patterndetermination processing. FIGS. 12A-12D are diagrams showing examples ofa recognition period pattern. FIGS. 13A and 13B are diagrams showingexamples of a transition of an image displayed by the projector 41. FIG.14 is a flowchart depicting an example of the flow of two-dimensionalbarcode display processing. FIG. 15 is a flowchart depicting an exampleof the flow of two-dimensional barcode acquisition processing.

The speaker 28 places the projector 41 and the main terminal 2 in a roomwhere a presentation is to be made (meeting room, for example), andturns on the projector 41 and the main terminal 2. The speaker 28 thenconnects the projector 41 and the main terminal 2 to the communicationline 5 to run the presentation program 20P in the main terminal 2.

The listeners 38 carry their own subsidiary terminals 3 to the room andturn on the subsidiary terminals 3. The listeners 38 then connect theirown subsidiary terminals 3 to the communication line 5 to launch thematerial viewer program 30P.

The speaker 28 then uses the presentation program 20P to open a file 7A.

With the main terminal 2, the main material display portion 204 startssending image data on Page 1, namely, the page 6AP1, to the projector 41based on display data 7A1 for the file 7A. The projector 41 receives theimage data and displays the page 6AP1 based on the image data in theprojector screen.

Every time the speaker 28 performs predetermined operation, e.g.,presses a next page button, the main material display portion 204 stopssending the image data on the page 6AP which is currently displayed(hereinafter, referred to as the “current page”) and sends image data onthe next page 6AP to the projector 41.

In response to the image data received, the projector 41 displays thenext page 6AP based on the image data received in the projector screen.This changes the current page.

As described earlier, while a certain page 6AP is displayed as thecurrent page, the speaker 28 may prompt the listeners 38 to refer to asubsidiary material 6B corresponding to the page 6AP.

At this time, the speaker 28 performs predetermined operation, e.g.,presses a subsidiary material reference button, to enter a command todisplay a two-dimensional barcode.

In performing the predetermined operation, the speaker 28 asks all ofthe listeners 38 to photograph the projector screen. It is noted thatthe speaker 28 asks only the specific listener to photograph theprojector screen when the subsidiary material 6B corresponds to thesecond limited material.

The timing determination portion 205 then determines a time at which thesubsidiary terminals 3 start photographing (hereinafter, referred to asa “start time P0”) and a pattern of a period of time during which thetwo-dimensional barcode is recognized (hereinafter, referred to as a“recognition period pattern 8S”) in the following manner.

The timing determination portion 205 determines that the start time P0is a time at which a preset time has elapsed since the command wasentered. The start time P0 is an absolute time. For example, if the timeat which the command has been entered is “eleven thirty, fifteenseconds, and 20 milliseconds (11:30 a.m., 15:20)”, and the preset timeis “seven seconds”, then the timing determination portion 205 determinesthat the start time P0 is “eleven thirty, twenty-two seconds, and 20milliseconds (11:30 a.m., 22:20)”.

The timing determination portion 205 then determines the recognitionperiod pattern 8S based on the reference data 7A2 for the subsidiarymaterial 6B. The recognition period pattern 8S is sometimes differentfor each of the subsidiary terminals 3 of the specific listeners andeach of the subsidiary terminals 3 of the non-specific listeners.Hereinafter, the recognition period pattern 8S in the subsidiaryterminal 3 of the specific listener is referred to as a “first pattern8S1” and the recognition period pattern 8S in the subsidiary terminal 3of the non-specific listener is referred to as a “second pattern 8S2”.

The description goes on to a method for determining each of the firstpattern 8S1 and the second pattern 8S2. The description is given withreference to the flowchart of FIG. 11.

Where the subsidiary material attributes data 7D corresponding to thematerial code of the reference data 7A2 indicates “all listeners” as thedelivery target (YES in Step #801 of FIG. 11), the timing determinationportion 205 determines that both the first pattern 8S1 and the secondpattern 8S2 a correspond to a pattern_A (Steps #802 and #803).

As shown in FIG. 12A, the pattern_A is a pattern in which a recognitionperiod corresponds to a period of time Tm that comes every time Tb afterthe lapse of time Ta since the start time P0.

Alternatively, where the subsidiary material attributes data 7Dcorresponding to the material code of the reference data 7A2 indicates“specific listener” as the delivery target (NO in Step #801 and YES inStep #804), the timing determination portion 205 determines that thefirst pattern 8S1 corresponds to the pattern_A (Step #805) and thesecond pattern 8S2 corresponds to a pattern_B (Step #806).

As shown in FIG. 12B, the pattern_B is a pattern in which no recognitionperiod is provided.

Alternatively, where the subsidiary material attributes data 7Dcorresponding to the material code of the reference data 7A2 indicates“attributes-specific” as the delivery target (NO in Step #801 and NO inStep #804), the timing determination portion 205 determines that thefirst pattern 8S1 corresponds to a pattern_C (Step #807) and the secondpattern 8S2 corresponds to a pattern_D (Step #808).

As shown in FIG. 12C, the pattern_C is a pattern in which a recognitionperiod corresponds to a period of time Tm that comes every time Td afterthe lapse of time Tc since the start time P0. As shown in FIG. 12D, thepattern_D is a pattern in which a recognition period corresponds to aperiod of time Tm that comes every time Td after the lapse of time(Tc+Td/2) since the start time P0.

The time Ta, Tb, Tc, and Td is a few seconds each. For example, the timeTa and the time Tc are one to five seconds each; the time Tb is three toten seconds; and the time Tb is six to ten seconds.

The time Tm is shorter than each of the time Ta, Tb, Tc, and Td. Thetime Tm is 0.1 to 2.0 seconds, for example. It is desirable that thetime Tm has a length enough for the digital camera 30 h to adjust thefocus of a lens on the two-dimensional barcode.

When the timing determination portion 205 determines the start time P0,the first pattern 8S1, and the second pattern 8S2, the timing notifyingportion 206 sends first timing data 7E1 to the subsidiary terminal 3 ofthe specific listener and sends second timing data 7E2 to the subsidiaryterminals 3 of the non-specific listeners. The first timing data 7E1indicates the start time P0 and the first pattern 8S1. The second timingdata 7E2 indicates the start time P0 and the second pattern 8S2.

The subsidiary terminal 3 of the specific listener and the subsidiaryterminals 3 of the non-specific listeners are identifiable based on thelistener data 7C (see FIG. 8). To be specific, the subsidiary terminal 3of the specific listener is the subsidiary terminal 3 corresponding tothe listener data 7C which indicates “full” in the access right. Thesubsidiary terminals 3 of the non-specific listeners are the subsidiaryterminals 3 corresponding to the listener data 7C which indicates “some”in the access right.

When the timing determination portion 205 determines the start time P0,the first pattern 8S1, and the second pattern 8S2, the two-dimensionalbarcode display portion 207 performs processing for displaying atwo-dimensional barcode based on the reference data 7A2 on the currentpage and the subsidiary material attributes data 7D (see FIG. 9) on thesubsidiary material 6B corresponding to the current page. The processingis executed in the steps as depicted in FIG. 14.

The two-dimensional barcode display portion 207 generates, based on thesubsidiary material attributes data 7D, a two-dimensional barcode thatindicates information used to download the subsidiary material 6B fromthe material server 1 (Step #811 of FIG. 14).

The information for download is, for example, a Uniform Resource Locator(URL). Suppose that the domain name of the material server 1 is“www.example.com”; the name of the subsidiary material storage portion101 is “folder-x”; the file name “list.doc” is indicated in thesubsidiary material attributes data 7D. In such a case, thetwo-dimensional barcode display portion 207 generates a two-dimensionalbarcode which indicates a URL“http://www.example.com/folder-x/list.doc”. The case is described belowin which the URL is used as the information used to download thesubsidiary material 6B

If the subsidiary material attributes data 7D indicates a second filename (YES in Step #812), then the two-dimensional barcode displayportion 207 generates a two-dimensional barcode which indicates an URLincluding the second file name instead of the file name (Step #813).

Hereinafter, the two-dimensional barcode generated in Step #811 isreferred to as a “first two-dimensional barcode 8A1” and thetwo-dimensional barcode generated in Step #813 is referred to as a“second two-dimensional barcode 8A2”. The format of each of the firsttwo-dimensional barcode 8A1 and the second two-dimensional barcode 8A2may be a known format such as a Quick Response (QR) code or a colorcode.

If the subsidiary material attributes data 7D corresponding to thematerial code of the reference data 7A2 indicates “all listeners” or“specific listener” as the delivery target (YES in Step #814), then thetwo-dimensional barcode display portion 207 transmits image data on thefirst two-dimensional barcode 8A1 instead of the image data on thecurrent page to the projector 41 (Step #817) during a periodcorresponding to the first pattern 8S1 (YES in Step #816 and NO in Step#818). The transmission is made in an interval from when the currenttime reaches the start time P0 to when operation for changing thecurrent page such as pressing the next page button is performed (NO inStep #815). After the elapse of the period corresponding to the firstpattern 8S1 (YES in Step #818), the two-dimensional barcode displayportion 207 stops sending the image data on the first two-dimensionalbarcode 8A1 (Step #819). The main material display portion 204 thensends the image data on the current page to the projector 41.

Where the delivery target indicates “all listeners” or “specificlistener”, the first pattern 8S1 is determined to be the pattern_A asdescribed above. In such a case, the main material display portion 204and the two-dimensional barcode display portion 207 perform theprocessing. Then, as shown in FIG. 12A, after the lapse of time Ta fromthe start time P0, the image data on the first two-dimensional barcode8A1 is sent, only during the period of time Tm, to the projector 41every time Tb. During the other periods of time, the image data on thecurrent page is sent to the projector 41.

This enables displaying, only for the period of time Tm, the firsttwo-dimensional barcode 8A1 instead of the current page at constantintervals as shown in FIG. 13A.

If the subsidiary material attributes data 7D corresponding to thematerial code of the reference data 7A2 indicates “attributes-specific”as the delivery target (NO in Step #814), then the two-dimensionalbarcode display portion 207 transmits the image data on the firsttwo-dimensional barcode 8A1 instead of the image data on the currentpage to the projector 41 (Step #822) during the period corresponding tothe first pattern 8S1 (YES in Step #821 and NO in Step #823). Thetransmission is made in an interval from when the current time reachesthe start time P0 to when operation for changing the current page isperformed (NO in Step #820). After the elapse of the periodcorresponding to the first pattern 8S1 (YES in Step #823), thetwo-dimensional barcode display portion 207 stops sending the image dataon the first two-dimensional barcode 8A1 (Step #824). The main materialdisplay portion 204 then starts sending the image data on the currentpage to the projector 41.

Before the operation, the two-dimensional barcode display portion 207transmits image data on the second two-dimensional barcode 8A2 insteadof the image data on the current page to the projector 41 (Step #826)during a period corresponding to the second pattern 8S2 (YES in Step#825 and NO in Step #827). After the elapse of the period correspondingto the second pattern 8S2 (YES in Step #827), the two-dimensionalbarcode display portion 207 stops sending the image data on the secondtwo-dimensional barcode 8A2 (Step #828). The main material displayportion 204 then starts sending the image data on the current page tothe projector 41.

Where the delivery target indicates “attributes-specific”, the firstpattern 8S1 is determined to be the pattern_C and the second pattern 8S2is determined to be the pattern_D as described above. In such a case,the main material display portion 204 and the two-dimensional barcodedisplay portion 207 perform the processing. Then, as shown in FIG. 12C,after the lapse of time Tc from the start time P0, the image data on thefirst two-dimensional barcode 8A1 is sent, only during the period oftime Tm, to the projector 41 every time Td. Further, after the lapse oftime (Tc+Td/2) from the start time P0, the image data on the secondtwo-dimensional barcode 8A2 is sent, only during the period of time Tm,to the projector 41 every time Td. During a period of time other thanboth the periods of time, the image data on the current page is sent tothe projector 41.

As shown in FIG. 13B, this enables displaying, only for the period oftime Tm, the first two-dimensional barcode 8A1 and the secondtwo-dimensional barcode 8A2 alternately instead of the current page atconstant intervals.

In response to the current page changed, the photographing stop commandportion 208 sends end command data 7F to each of the subsidiaryterminals 3 to instruct the same to finish photographing.

In the meantime, each of the listeners 38 follows guidance by thespeaker 28 to direct his/her subsidiary terminal 3 toward the projectorscreen to photograph the projector screen.

With each of the subsidiary terminals 3, the photographing start portion301 (see FIG. 5) receives the first timing data 7E1 or the second timingdata 7E2 from the main terminal 2 to cause the digital camera 30 h tostart photographing.

In response to the first timing data 7E1 or the second timing data 7E2received, the image capturing portion 302 captures, as a target image8B, an image shot by the digital camera 30 h. The two-dimensionalbarcode extraction portion 303 then extracts a two-dimensional barcodefrom the target image 8B. The processing for capturing and extraction isexecuted in the steps as depicted in FIG. 15.

When the first timing data 7E1 is received, the image capturing portion302 captures (Step #833), as the target image 8B, an image shot by thedigital camera 30 h from when the current time reaches the start time P0indicated in the first timing data 7E1 to when the end command data 7Fis sent from the main terminal 2 (NO in Step #831 of FIG. 15) during aperiod corresponding to the first pattern 8S1 indicated in the firsttiming data 7E1 (YES in Step #832 and NO in Step #836). It is noted thatcapturing is prohibited at a time other than the period corresponding tothe first pattern 8S1.

To be specific, the target images 8B are captured one after anotherduring the period corresponding to the first pattern 8S1. Every time thetarget image 8B is captured, the two-dimensional barcode extractionportion 303 attempts to extract a two-dimensional barcode from thetarget image 8B (Step #834).

When the two-dimensional barcode extraction portion 303 extracts thetwo-dimensional barcode successfully (YES in Step #835), the imagecapturing portion 302 and the two-dimensional barcode extraction portion303 finish the processing for capturing and extraction (Step #838).

Alternatively, after the elapse of the period (YES in Step #836), theimage capturing portion 302 and the two-dimensional barcode extractionportion 303 stop the capturing and extraction (Step #837), and wait forthe time to reach the next period of time.

According to the processing depicted in FIG. 15, where the first timingdata 7E1 indicates the pattern_A as the first pattern 8S1, as shown inFIG. 12A, the target image 8B is captured and extracting thetwo-dimensional barcode is attempted, only for the period of time Tm,every time Tb after the lapse of time Ta from the start time P0. Sinceno target image 8B is captured in a time other than the period of timeTm, no two-dimensional barcodes can be extracted.

Where the first timing data 7E1 indicates the pattern_C as the firstpattern 8S1, as shown in FIG. 12C, the target image 8B is captured andextracting the two-dimensional barcode is attempted, only for the periodof time Tm, every time Td after the lapse of time Tc from the start timeP0. Since no target image 8B is captured in a time other than the periodof time Tm, no two-dimensional barcodes can be extracted.

The flow of the processing for the case where the second timing data 7E2is received is basically the same as that for the case where the firsttiming data 7E1 is received, which is shown in FIG. 15. However, thestart time P0 indicated in the second timing data 7E2 is used as thestart time P0, and, instead of the first pattern 8S1, the second pattern8S2 indicated in the second timing data 7E2 is used.

According to the processing depicted in FIG. 15, where the second timingdata 7E2 indicates the pattern_A as the second pattern 8S2, as shown inFIG. 12A, the target image 8B is captured and extracting thetwo-dimensional barcode is attempted, only for the period of time Tm,every time Tb after the lapse of time Ta from the start time P0. Sinceno target image 8B is captured in a time other than the period of timeTm, no two-dimensional barcodes can be extracted.

Where the second timing data 7E2 indicates the pattern_D as the secondpattern 8S2, as shown in FIG. 12D, the target image 8B is captured andextracting the two-dimensional barcode is attempted, only for the periodof time Tm, every time Td after the lapse of time (Tc+Td/2) from thestart time P0. Since no target image 8B is captured in a time other thanthe period of time Tm, no two-dimensional barcodes can be extracted.

Where the second timing data 7E2 indicates the pattern_B as the secondpattern 8S2, as shown in FIG. 12B, there is no period of time forcapturing. No two-dimensional barcodes are thus extracted.

A two-dimensional barcode extracted in response to the first timing data7E1 received is the first two-dimensional barcode 8A1. A two-dimensionalbarcode extracted in response to the second timing data 7E2 received isthe second two-dimensional barcode 8A2.

The text recognition portion 304 decodes the two-dimensional barcode(the first two-dimensional barcode 8A1 or the second two-dimensionalbarcode 8A2) extracted by the two-dimensional barcode extraction portion303 to obtain text data. In this way, text data indicating the URL isobtained.

The subsidiary material obtaining portion 305 obtains the file 7B basedon the URL in the following manner. The subsidiary material obtainingportion 305 accesses the material server 1 based on the URL. Thesubsidiary material obtaining portion 305 then requests the file 7Bidentified by the URL from the material server 1.

With the material server 1, the subsidiary material delivery portion 102retrieves the file 7B requested from the subsidiary material storageportion 101 to send the retrieved file 7B to the subsidiary terminal 3.The subsidiary material obtaining portion 305 then receives the file 7B.

The subsidiary material display portion 306 displays the subsidiarymaterial 6B based on the file 7B in the touch-sensitive panel display 30e 1.

FIG. 16 is a flowchart depicting an example of the flow of the entireprocessing by the main terminal 2. FIG. 17 is a flowchart depicting anexample of the flow of the entire processing by the subsidiary terminal3.

The description goes on to the flow of the entire processing by each ofthe main terminal 2 and the subsidiary terminals 3. The description isgiven with reference to the flowcharts.

The main terminal 2 performs the processing based on the presentationprogram 20P in the steps as depicted in FIG. 16.

The main terminal 2 opens a file 7A and starts sending, to the projector41, image data on Page 1 of a main material 6A, namely, image data onpage 6AP1 (see FIG. 7), as the image data on the current page (Steps#851 and #852 of FIG. 16).

Where the subsidiary material reference button is pressed or the like toenter a command to display a two-dimensional barcode (YES in Step #853),the main terminal 2 determines a pattern of period during which thetwo-dimensional barcode is displayed (recognition period pattern 8S) anda time at which to start displaying the two-dimensional barcode (starttime P0) (Step #854). The determination processing is performed in thesteps of FIG. 11.

The main terminal 2 then performs processing for notifying thesubsidiary terminals 3 of the start time P0 and recognition periodpattern 8S (first pattern 8S1 or second pattern 8S2) thus determined(Step #855), and processing for displaying the two-dimensional barcode(Step #856).

The main terminal 2 performs the notification processing by sending thefirst timing data 7E1 to the subsidiary terminal 3 of the specificlistener and sending the second timing data 7E2 to the subsidiaryterminals 3 of the non-specific listeners. The processing for displayingthe two-dimensional barcode is performed in the steps depicted in FIG.14.

When a command to change the current page to the next page is entered(YES in Step #857), the main terminal 2 sends the end command data 7F tothe subsidiary terminals 3 (Step #858), and starts sending, to theprojector 41, image data on the next page as the image data on thecurrent page (Step #861 and Step #852) unless the current page is thefinal page (NO in Step #860).

Where a command to change the current page to the next page is entered(YES in Step #859) without entry of a command to display atwo-dimensional barcode (NO in Step #853), the main terminal 2 startssending, to the projector 41, the image data on the next page as theimage data on the current page (Step #861 and Step #852) unless thecurrent page is the final page (NO in Step #860). The main terminal 2,however, sends no end command data 7F.

On the other hand, the subsidiary terminal 3 performs the processingbased on the material viewer program 30P in the steps as depicted inFIG. 17.

When receiving the first timing data 7E1 or the second timing data 7E2(YES in Step #871 of FIG. 17), the subsidiary terminal 3 performsprocessing for extracting the two-dimensional barcode (firsttwo-dimensional barcode 8A1 or second two-dimensional barcode 8A2) (Step#872). The processing steps are described earlier with reference to FIG.15.

When extracting the two-dimensional barcode successfully (YES in Step#873), the subsidiary terminal 3 decodes the two-dimensional barcode toacquire text data (Step #874) and obtains (downloads) a file 7B from thematerial server 1 based on an URL indicated in the text data (Step#875). The subsidiary terminal 3 then displays the subsidiary material6B based on the file 7B (Step #876).

While the presentation program 20P is running (YES in Step #877), thesubsidiary terminal 3 performs the processing of Steps #871 to #876appropriately.

In this embodiment, it is possible to deliver a material such as thesubsidiary material 6B to attendees, e.g., the listeners 38, accordingto the attributes thereof more easily than is conventionally possible.

FIGS. 18A-18C are timing charts depicting examples of a time at which aspecific listener and a non-specific listener each photographs withhis/her subsidiary terminal 3. FIG. 19 is a timing chart depicting amodified example of a time at which a specific listener and anon-specific listener each photographs with his/her subsidiary terminal3. FIGS. 20A and 20B are diagrams showing examples of restoration of thefirst two-dimensional barcode 8A1. FIGS. 21A-21D are timing chartsdepicting examples of a time of recognition and display when the threefiles 7A are distributed selectively.

In this embodiment, the timing determination portion 205 of the mainterminal 2 determines the first pattern 8S1 and the second pattern 8S2depending on the type of the subsidiary material 6B, namely, dependingon whether the subsidiary material 6B is the first limited material, thesecond limited material, or the no-limit material. The timing notifyingportion 206 notifies the subsidiary terminal 3 of the specific listenerof the start time P0 and the first pattern 8S1, and notifies thesubsidiary terminals 3 of the non-specific listeners of the start timeP0 and the second pattern 8S2.

Instead of this, however, another arrangement is possible. To bespecific, the first pattern 8S1 and the second pattern 8S2 arepredefined in a fixed manner, the timing determination portion 205determines the start time P0 only, and the timing notifying portion 206informs the subsidiary terminals 3 of the start time P0 only. In such acase, the main terminal 2 and the subsidiary terminal 3 are required toperform the processing in the following manner.

For example, in the subsidiary terminal 3 of the specific listener, thepattern_C shown in FIG. 12C is defined as the first pattern 8S1 in afixed manner. In the subsidiary terminals 3 of the non-specificlisteners, the pattern_D shown in FIG. 12D is defined as the secondpattern 8S2 in a fixed manner.

If the subsidiary material 6B corresponding to the current page is theno-limit material, in other words, if the delivery target is “alllisteners”, then the two-dimensional barcode display portion 207 sends,to the projector 41, the image data on the first two-dimensional barcode8A1 at a timing as shown in the pattern_A of FIG. 12A. This allows thespecific listener and the non-specific listeners to capture the firsttwo-dimensional barcode 8A1 as shown in FIG. 18A.

Alternatively, if the subsidiary material 6B corresponding to thecurrent page is the second limited material, in other words, if thedelivery target is “some”, then the two-dimensional barcode displayportion 207 sends, to the projector 41, the image data on the firsttwo-dimensional barcode 8A1 at a timing as shown in the pattern_C ofFIG. 12C. This allows the specific listener to capture the firsttwo-dimensional barcode 8A1; however does not allow any of thenon-specifics listener to capture the first two-dimensional barcode 8A1as shown in FIG. 18B.

Alternatively, if the subsidiary material 6B corresponding to thecurrent page is the first limited material, in other words, if thedelivery target is “attributes-specific”, then the two-dimensionalbarcode display portion 207 sends, to the projector 41, the image dataon the first two-dimensional barcode 8A1 at a timing as shown in thepattern_C of FIG. 12C, and sends, to the projector 41, the image data onthe second two-dimensional barcode 8A2 at a timing as shown in thepattern_D of FIG. 12D. This allows: the specific listener to capture,among the first two-dimensional barcode 8A1 (corresponding to the thicksolid line of FIG. 18C) and the second two-dimensional barcode 8A2(corresponding to the dot-dash line), only the first two-dimensionalbarcode 8A1; and the non-specific listeners to capture only the secondtwo-dimensional barcode 8A2 as shown in FIG. 18C.

If the subsidiary material 6B corresponding to the current page is thefirst limited material, then the main terminal 2 and the subsidiaryterminal 3 may perform the processing in the following manner.

The timing determination portion 205 determines that the first pattern8S1 is the pattern_A and notifies the subsidiary terminal 3 of thespecific listener that the first pattern 8S1 is the pattern_A. Thetiming determination portion 205 determines that the second pattern 8S2is the pattern_D and notifies the subsidiary terminals 3 of thenon-specific listeners that the second pattern 8S2 is the pattern_D.

The two-dimensional barcode display portion 207 generates even number oftwo-dimensional barcode pieces 8C each of which corresponds to a part ofthe first two-dimensional barcode 8A1. After the current time reachesthe start time P0, the two-dimensional barcode display portion 207causes the projector 41 to display, at the timing shown as thepattern_A, the two-dimensional barcode pieces 8C one by one repeatedly.

For example, as shown in FIG. 19, the two-dimensional barcode displayportion 207 displays four two-dimensional barcode pieces 8C1-8C4 one byone in order repeatedly.

In the meantime, overlapping the two-dimensional barcode pieces 8C1-8C4results in the first two-dimensional barcode 8A1. Stated differently,any part of the first two-dimensional barcode 8A1 is always seen in atleast one of the two-dimensional barcode pieces 8C1-8C4.

In order for the subsidiary terminal 3 to obtain the reference positionfor overlapping, it is desirable to generate the two-dimensional barcodepieces 8C in a manner to prevent three position detection patterns(black squares) from lacking.

However, even if all of the even-numbered two-dimensional barcode pieces8C are overlapped with one another, specifically in FIG. 19, even if thetwo-dimensional barcode pieces 8C2 and 8C4 are overlapped with eachother, the first two-dimensional barcode 8A1 cannot be restored. It isdesirable to set an error correction level of the first two-dimensionalbarcode 8A1 at a low level in order to prevent text data from beingdecoded with a part of the first two-dimensional barcode 8A1 lacked. Forexample, it is desirable to set the error correction level at L (7%).

With the subsidiary terminal 3 of the specific listener, the imagecapturing portion 302 captures, as the target images 8B, imagesphotographed by the digital camera 30 h one after another at the timingshown in the pattern_A. The two-dimensional barcode extraction portion303 overlaps the target images 8B with one another to attempt to restore(reproduce) the first two-dimensional barcode 8A1.

This allows all of the two-dimensional barcode pieces 8C1-8C4 to becaptured as shown in FIG. 20A, leading to restoration of the firsttwo-dimensional barcode 8A1.

On the other hand, with each of the subsidiary terminals 3 of thenon-specific listeners, the image capturing portion 302 captures, as thetarget images 8B, images photographed by the digital camera 30 h oneafter another at the timing shown in the pattern_D. The two-dimensionalbarcode extraction portion 303 overlaps the target images 8B with oneanother to attempt to restore the first two-dimensional barcode 8A1.

However, as shown in FIG. 20B, only the two-dimensional barcode pieces8C2 and 8C4 of the two-dimensional barcode pieces 8C1-8C4 can becaptured. The two-dimensional barcode extraction portion 303 thus cannotrestore the first two-dimensional barcode 8A1.

In this embodiment, as the first two-dimensional barcode 8A1 and thesecond two-dimensional barcode 8A2, a two-dimensional barcoderepresenting a URL of the file 7B is generated. Instead of this,however, it is possible to generate a two-dimensional barcoderepresenting the identification code or the second identification code(see FIG. 9) of the file 7B.

In such a case, the subsidiary terminal 3 stores, in advance, a domainname of the material server 1 and a folder name of the subsidiarymaterial storage portion 101. The subsidiary terminal 3 also stores,therein, the correspondence between the identification code or thesecond identification code of each of the files 7B and the file name ofeach of the files 7B. The subsidiary material obtaining portion 305 thendownloads the file 7B based on these information pieces in the followingmanner.

When the first two-dimensional barcode 8A1 or the second two-dimensionalbarcode 8A2 is extracted and encoded to acquire text data, thesubsidiary material obtaining portion 305 identifies a file namecorresponding to the identification code or the second identificationcode indicated in the text data. The subsidiary material obtainingportion 305 then accesses the subsidiary material storage portion 101 ofthe material server 1 to download a file 7B given the identified filename from the subsidiary material storage portion 101.

In this embodiment, where a certain page 6AP corresponds to the currentpage, the material server 1 provides the subsidiary terminal 3 of thespecific listener with a file 7B having content given no limitation, andprovides the subsidiary terminals 3 of the non-specific listeners with afile 7B having limited content. In short, the material server 1selectively sends two files 7B having different contents depending onthe attributes of the subsidiary terminals 3.

Instead of this, however, the material server 1 may selectively transmitthree or more files 7B having different contents. A mechanism for thetransmission is described below by taking an example in which threefiles 7B1-7B3 having different contents are sent.

The listeners 38 are classified into any one of first attributes, secondattributes, and third attributes depending on departments which thelisteners 38 work in.

With the main terminal 2, the timing determination portion 205determines that the recognition period patterns 8S of the subsidiaryterminal 3 of the listener 38 who corresponds to the first attributes,the subsidiary terminal 3 of the listener 38 who corresponds to thesecond attributes, and the subsidiary terminal 3 of the listener 38 whocorresponds to the third attributes are the pattern_D of FIG. 21A, thepattern_E of FIG. 21B, and the pattern_F of FIG. 21C, respectively.

The timing notifying portion 206 notifies each of the subsidiaryterminals 3 of the start time P0 and the recognition period pattern 8Sdetermined by the timing determination portion 205.

After the start time P0, the two-dimensional barcode display portion 207sends, to the projector 41, image data on a two-dimensional barcoderepresenting an URL of the file 7B1 at the timing shown in thepattern_D. The two-dimensional barcode display portion 207 sends, to theprojector 41, image data on a two-dimensional barcode representing anURL of the file 7B2 at the timing shown in the pattern_E. Thetwo-dimensional barcode display portion 207 sends, to the projector 41,image data on a two-dimensional barcode representing an URL of a file7B3 at the timing shown in the pattern_F. This allows, as shown in FIG.21D, the current page and the three two-dimensional barcodes to bedisplayed in order repeatedly.

With the subsidiary terminal 3 of the listener 38 who corresponds to thefirst attributes, the image capturing portion 302 captures, after thestart time P0, an image photographed by the digital camera 30 h as thetarget image 8B at the timing shown in the pattern_D. Thetwo-dimensional barcode extraction portion 303 extracts atwo-dimensional barcode from the target image 8B. This extracts only thetwo-dimensional barcode corresponding to the file 7B1. The subsidiarymaterial obtaining portion 305 then downloads the file 7B1.

Similarly, with the subsidiary terminal 3 of the listener 38 whocorresponds to the second attributes, the image capturing portion 302captures an image photographed by the digital camera 30 h as the targetimage 8B at the timing shown in the pattern_E. The two-dimensionalbarcode extraction portion 303 then extracts a two-dimensional barcodefrom the target image 8B. This extracts only the two-dimensional barcodecorresponding to the file 7B2. The subsidiary material obtaining portion305 then downloads the file 7B2.

Similarly, with the subsidiary terminal 3 of the listener 38 whocorresponds to the third attributes, the image capturing portion 302captures an image photographed by the digital camera 30 h as the targetimage 8B at the timing shown in the pattern_F. The two-dimensionalbarcode extraction portion 303 then extracts a two-dimensional barcodefrom the target image 8B. This extracts only the two-dimensional barcodecorresponding to the file 7B3. The subsidiary material obtaining portion305 then downloads the file 7B3.

In this embodiment, when the file 7B is given to the listeners 38, atwo-dimensional barcode representing a URL of the file 7B is displayed.Instead of such a two-dimensional barcode, a barcode representing theURL (so-called one-dimensional barcode) may be displayed. Instead of theURL, a barcode representing an identification code or a secondidentification code of the file 7B may be displayed.

In this embodiment, the main terminal 2 displays the main material 6A,the first two-dimensional barcode 8A1, and the second two-dimensionalbarcode 8A2 with the projector 41. Instead of the projector 41, a liquidcrystal display or a plasma display may be used for display. Where theimage forming apparatus 42 is provided with a large touch-sensitivepanel display, such a touch-sensitive panel display may be used fordisplay.

The main terminal 2 and the projector 41 may be configured as onedevice. For example, the projector 41 may be a projector which has anOperating System (OS) used in a personal computer or a tablet computer,namely, a so-called smart projector. In such a case, the projector 41may execute the presentation program 20P thereon.

In this embodiment, the two-dimensional barcode display portion 207generates the first two-dimensional barcode 8A1 or the secondtwo-dimensional barcode 8A2 without encrypting a URL. Instead of thisarrangement, it is also possible to generate a two-dimensional barcoderepresenting an encrypted URL as the first two-dimensional barcode 8A1or the second two-dimensional barcode 8A2. In such a case, a commondecryption key is prepared in each of the subsidiary terminals 3. Thetwo-dimensional barcode display portion 207 encrypts a URL so that thecommon decryption key can decrypt the URL. The two-dimensional barcodedisplay portion 207 then generates a two-dimensional barcoderepresenting the encrypted URL.

In this embodiment, until a command to change the current page to thenext page is entered, the main terminal 2 displays a two-dimensionalbarcode at constant intervals and the subsidiary terminals 3 capture animage at constant intervals. Instead of this, the main terminal 2 maystop displaying and the subsidiary terminals 3 may stop capturing when atwo-dimensional barcode is displayed at a predetermined number of times,even before the command is entered. Alternatively, the main terminal 2may stop displaying and the subsidiary terminals 3 may stop capturingwhen a predetermined time has elapsed or when the speaker 28 performspredetermined operation.

It is to be understood that the overall configuration of the materialdisplay system 100, the material server 1, the main terminal 2, and thesubsidiary terminals 3, the constituent elements thereof, the content ofthe processing, the order of the processing, the structure of the data,and the like may be appropriately modified without departing from thespirit of the present invention.

Although embodiments of the present invention have been described andillustrated in detail, the disclosed embodiments are made for purposesof illustration and example only and not limitation. The scope of thepresent invention should be interpreted by terms of the appended claims.

What is claimed is:
 1. An image display system comprising: a displaycontrol device configured to control a display unit to display an image;a plurality of terminals; and a transmitter configured to transmit, toeach of the plurality of terminals, respective timing data correspondingto respective specific periods of time, the timing data includingdifferent times indicating when different code images are displayed tothe plurality of terminals; wherein each of the terminals includes ahardware processor configured to: extract, from an image displayed bythe control device and photographed by the terminal during therespective specific period of time corresponding to the terminal of thehardware processor, a code image representing a code for identifying amaterial stored in a server; and obtain the code by decoding the codeimage, and a receiver configured to obtain a material from the serverbased on the code obtained by the hardware processor, the displaycontrol device includes a controller configured to control the displayunit to display the code image, in a first terminal of the terminals,the specific period of time is a first period of time indicating onlywhen a first code image is displayed by the display control device, in asecond terminal of the terminals, the specific period of time is asecond period of time indicating only when a second code image isdisplayed by the display control device and does not overlap the firstperiod of time, and the controller controls the display unit to displaya particular code image as the code image for the first period of timeand to display a particular, different code image as the code image forthe second period of time, each particular code image representing, asthe code, a code for identifying a particular material fetched from theserver by the terminals according to the first and second periods oftime.
 2. The system according to claim 1, wherein the first code imagerepresents a first code for identifying a first particular material andthe second code image represents a second code for identifying a secondparticular material.
 3. The system according to claim 2, wherein thecontroller controls the display unit to display a main materialprimarily used in a presentation for a third period of time thatoverlaps neither of the first period of time and the second period oftime.
 4. The system according to claim 2, wherein the transmitter isconfigured to inform, among the terminals, the first terminal to whichthe particular material is to be provided of the first period of time,and to inform the second terminal to which the second particularmaterial is to be provided of the second period of time.
 5. The systemaccording to claim 2, wherein the first period of time is reached aplurality of times after a lapse of predetermined time, and the secondperiod of time is reached a plurality of times after the lapse of thepredetermined time.
 6. The system according to claim 2, wherein thefirst code image and the second code image are images representing thefirst code and the second code respectively in a form incomprehensibleto a human being.
 7. An image display system comprising: a displaycontrol device configured to control a display unit to display an image;a plurality of terminals; and a transmitter configured to transmit, toeach of the plurality of terminals, respective timing data correspondingto a respective specific periods of time, the timing data includingdifferent times indicating when different code images are displayed tothe plurality of terminals; wherein the display control device includesa controller configured to control the display unit to display aplurality of different parts of a code image according to apredetermined timing pattern of the timing data for the first period oftime indicating only when a first code image is displayed by the displaycontrol device, and to display a particular, second different code imagefor the second period of time indicating only when a second part of acode image is displayed by the display control device, each particularcode image representing a code for identifying a material stored in aserver fetched from the server by the terminals according to the firstand second periods of time, each of the terminals includes a hardwareprocessor configured to: obtain a combined code image by combining theplurality of different parts and the different code image displayed bythe control device and photographed by a terminal during the respectivespecific period of time corresponding to the terminal of the hardwareprocessor; and decode the combined code image to obtain a code, and areceiver configured to obtain a material from the server based on thecode obtained by the hardware processor, in a first terminal of theterminals, the first period of time is set as the specific period oftime, and in a second terminal of the terminals, a second period of timedifferent from the first period of time and indicating only when asecond code image is displayed by the display control device is set asthe specific period of time.
 8. The system according to claim 7, whereinthe first code image represents a first code for identifying a firstparticular material and the second code image represents a second codefor identifying a second particular material.
 9. The system according toclaim 8, wherein the controller controls the display unit to display amain material primarily used in a presentation for a third period oftime that overlaps neither of the first period of time and the secondperiod of time.
 10. The system according to claim 8, wherein thetransmitter is configured to inform, among the terminals, the firstterminal to which the particular material is to be provided of the firstperiod of time, and to inform the second terminal to which the secondparticular material is to be provided of the second period of time. 11.The system according to claim 8, wherein the first period of time isreached a plurality of times after a lapse of predetermined time, andthe second period of time is reached a plurality of times after thelapse of the predetermined time.
 12. The system according to claim 8,wherein the first code image and the second code image are imagesrepresenting the first code and the second code respectively in a formincomprehensible to a human being.
 13. A method of displaying images andobtaining material in an image display system, the image display systemcomprising a display control device configured to control a display unitto display an image, a plurality of terminals, and a transmitterconfigured to transmit, to each of the plurality of terminals,respective timing data corresponding to respective specific periods oftime, the timing data including different times indicating whendifferent code images are displayed to the plurality of terminals,wherein in a first terminal of the terminals, the specific period oftime is a first period of time indicating only when a first code imageis displayed by the display control device, and in a second terminal ofthe terminals, the specific period of time is a second period of timeindicating only when a second code image is displayed by the displaycontrol device and does not overlap the first period of time, the methodcomprising: extracting, by a hardware processor of a terminal of theplurality of terminals, from an image displayed by the control deviceand photographed by the terminal during the respective specific periodof time corresponding to the terminal of the hardware processor, a codeimage representing a code for identifying a material stored in a server;obtaining, by the hardware processor, the code by decoding the codeimage; obtaining, by a receiver of the terminal, a material from theserver based on the code obtained by the hardware processor; andcontrolling, by a controller of the display device, the display unit todisplay a particular code image as the code image for the first periodof time and to display a particular, different code image as the codeimage for the second period of time, each particular code imagerepresenting, as the code, a code for identifying a particular materialfetched from the server by the terminals according to the first andsecond periods of time.
 14. A method of displaying images and obtainingmaterial in an image display system, the image display system comprisinga display control device configured to control a display unit to displayan image, a plurality of terminals, and a transmitter configured totransmit, to each of the plurality of terminals, respective timing datacorresponding to respective specific periods of time, the timing dataincluding different times indicating when different code images aredisplayed to the plurality of terminals, wherein in a first terminal ofthe terminals, the first period of time indicates only when a first codeimage is displayed by the display control device and is set as thespecific period of time, and in a second terminal of the terminals, asecond period of time different from the first period of time andindicating only when a second code image is displayed by the displaycontrol device is set as the specific period of time, the methodcomprising: controlling, by a controller of the display control devicethe display unit to display a plurality of different parts of a codeimage according to a predetermined timing pattern of the timing data forthe first period of time indicating only when a first code image isdisplayed by the display control device, and to display a particular,different code image as the code image for the second period of time,each particular code image representing a code for identifying amaterial stored in a server fetched from the server by the terminalsaccording to the first and second periods of time; combining, by thehardware processor of a terminal of the plurality of terminals, theplurality of different parts and the different code to obtain a combinedcode image based on a plurality of images displayed by the controldevice and photographed by the terminal during the respective specificperiod of time corresponding to the terminal of the hardware processor;obtaining, by the hardware processor, the code by decoding the codeimage, and obtaining, by a receiver of the terminal, a material from theserver based on the code obtained by the hardware processor.